Image restoration refers to restoring and reconstructing damaged images such that a viewer cannot find out that the images have been restored. Traditional methods for image restoration mainly consist of two types: diffusion-based restoration method in which the information is diffused from an undamaged area to an area to be restored by a diffusion mechanism and texture-synthesis-based method in which pixel blocks which are similar with boundary pixels of the damaged area are searched near the damaged area, and then the pixel blocks obtained by the searching are copied under certain structural constraints and the seams among the pixel blocks are filled.
All traditional methods for image restoration assume that there are dislocations among image blocks of the images to be restored, i.e., there are overlapping areas among image blocks. However, the case that there is no overlapping area between the image blocks often occurs during actual image restoration. Therefore, the two types of methods mentioned above will not be suitable for restoring of any of damaged images.
Therefore, another image restoration method is provided, in which extrapolation is performed on the image blocks without overlapping such that these image blocks are overlapped in the extrapolation area, and then the extrapolated image blocks are registered to achieve the restoration of the image without overlapping area.
However, the extrapolation performed on the image blocks is very inaccurate and the registering by means of the extrapolation area will further increase the error. Besides, such image restoration method can only be suitable for square image blocks. Therefore, although this method can achieve the restoration of the image without overlapping area, the use of this method is limited and the accuracy of the restoration of the image cannot be ensured.